Heretofore various internal combustion piston-type engines have been provided which, however, because of inherent design characteristics are beset with one or more of the following shortcomings: (a) the heat of combustion causes inordinate thermal loads to be imposed on the engine cooling system; (b) the thermodynamic efficiency of the cylinder is poor; (c) a substantial amount of energy produced by the combustion gases is wasted; and (d) excessive wear of the cylinder liner, piston rings and seals occurs due to the inordinately high temperature to which they are subjected during operation of the engine.